Core C. Protein Production Core Director: Jinwoo Ahn, PhD The Protein Production Core will be primarily responsible for producing mg quantities of homogenous, pure (>95%) virus encoded proteins, human cellular partners, and their complexes for structural studies. Secondarily, the core will support biophysical and bioanalytical characterization studies of these proteins and protein complexes to aid in refining the biochemical bases for atomic and molecular determination of proteins and complexes. It is particularly important to produce correctly folded and mono-dispersed solutions of the material. The amounts and properties of purified proteins that are necessary for NMR or crystallographic structure determination are frequently underestimated when planning structural biology projects. We, therefore, place strong emphasis on providing high quality material for analysis through the PCHPI. To this end, a general approach as follows is proposed.